The silicon type delay composition was prepared by co-precipitation and hand-mixed.Based on the analysis of electron microscopy, EDS spectra and X-ray diffraction, BaSO₄ and little (BaPb) SO₄ were found out and part of silicon and Pb₃O₄ were coated by BaSO₄ during the process of co-precipitation. The delay time and burning rate of the delay compositions were measured by light-sensitive detector. Results show that the average burning rate of the delay composition prepared by co-precipitation is 1.25 mm·s^-1, slower than that of hand-mixed, which is 1.41 mm·s^-1. The delay precision of the delay composition prepared by co-precipitation was better than that of hand-mixed one. The standard deviation of burning rate of the co-precipitation composition is 0.073, and that of the composition prepared by hand-mixed is 0.25.